Yes, here is another thing that strikes me as odd, but maybe I am just plain wrong. The only available mail log I have (that ever contains information, including what you'll see here) is located in this file path:

/var/spool/mail/root This is also where all client logs are located...only they are all filesize 0 (empty). Never anything here:

/var/log/mail Only /statistics. Anyhow, here is a pretty well repetitive error log.